1. Field
The present disclosure relates to a method of forming a pattern structure for a semiconductor device, and more particularly, to a method of forming a line-shaped pattern structure having a node separation area for a semiconductor device.
2. Discussion of the Related Art
As the degree of integration of semiconductor devices increases, conductive structures and wiring structures for the semiconductor device tend to be downsized and become denser and denser. To address such semiconductor device trends, intensive research has been conducted to develop fine pattern structures for the semiconductor devices. In this regard, a double patterning technology has been suggested for forming repeated lines having line widths less than a marginal resolution of the conventional photolithography process. For example, such double patterning technology can include double exposures where two separate exposures of the same photoresist layers use two different photomasks. According to the double patterning technology, a uniform and simple line-shaped pattern having a uniform line width and gap distance may be repeatedly formed on a substrate with relatively high quality.
However, it can be difficult to form a non-uniform or a complicated line-shaped pattern using double-patterning technology. For example, when the line-shaped pattern is cut off or broken such that the line-shaped pattern becomes discontinuous in a longitudinal direction, much like a node separation area in a cell region, an additional mask pattern is needed for forming the cut-off portion of the line-shaped pattern. Since the width and gap distance of the line-shaped pattern is very small and fine the size of the cut-off portion of the pattern also becomes very small. As such, the mask pattern becomes very hard to be accurately aligned with the cut-off portion of the line-shaped pattern. When the mask pattern is not accurately aligned with the cut-off portion, an unexpected portion of the line-shaped pattern is cut off such that the cut-off portion is positioned at an undesired position of the pattern. For example, the node separation of the line may not be arranged at a correct alignment position in a cell region of the substrate.
Accordingly, a need exists for a patterning process for forming a line-shaped pattern in which the cut-off portion can be accurately positioned.